Diffuser for portable electric fan



Aug. 18, 1959 R. c. PIPER, JR., ET AL 2,900,128

DIFFUSER FOR PORTABLE ELECTRIC FAN Filed Nov. 15, 1956 Unite St te PM.

1 Claim. (cream- 214 This invention relates to adiflfuser for a portable electric fan and more particularly to such a difiuser which is adapted to be mounted on the grid atthe outlet side of a portable electric fan and which serves to spread or enlarge the stream of air delivered by the fan radially so as to avoid the discharge of a-concentrated and unpleasant stream of air. A

One of the principal objects of the present invention is to provide such a diffuser which is free from vibration and noise under the influence of the electric fan or the stream of air deliveredby the electric fan.

Another object is to provide such a difiu'se'r which can be easily, quickly and securely attached to the foraminous grid at the outlet side of the fan and can be as easily and quickly detached therefrom when the diflusing action is not desired.

Another object is to provide such a diffuser which is very attractive in appearance and greatly enhances the appearance of the fan. 7

Another object is to provide such a dilfuser which is fully effective in eliminating concentrated streams of air delivered by the fanv and which serves to createa pleasant circulation by producing. radially broadened stream of air.

Another object is to .provide such a diifuser which is very lowin cost and composed of simple and inexpensive parts which are readily assembled together.

Another objectistoprovide. sucha .difi'user which is strong and durableand will standup-under conditions of constant use and continuedattachment to and detachment from the currentof. the fanbei-ng served.

Other objects and advantages of-the invention will be apparent from the'following description and drawings in which:

Fig. 1 is a 'frontelevational-"viewof a portable electric ventilating fan having a diffuser embodying the present invention attached to the foraminous grid at its outlet side.

Fig. 2 is a vertical section taken generally on line 2-2, Fig. 1.

Fig. 3 is an enlarged section, similar to Fig. 2, through one side of the diffuser and showing the manner in which it is attached to the grid.

Fig. 4 is a fragmentary perspective view of the outer ring of the diifuser and in particular showing the plastic gripper used to secure the difiuser at four equally spaced intervals around its periphery to the grid of the fan.

The dilfuser embodying the present invention is designed to be used in conjunction with a portable ventilating fan such as is illustrated in the drawings and which is shown as including a sheet metal rectangular casing 5 having connected bottom, side and top walls jointly having inwardly extending flanges 6 and 8 at the inlet and outlet sides of the casing, the casing thereby having large generally rectangular openings at its opposite sides. The casing 5 can be provided with a handle 9 and within the casing is secured a vertical partition 10 which is provided with a marginal flange 1 1 engaging and suitably secured to the top, bottom and side walls of the casing.

2 This partition is provided with a large central circular opening 12 reinforced by a marginal flange 13 which is shown as projecting toward the discharge side of the fan.

Within the casing on the inlet side of the partition 10 is arranged a U-shaped cross bar 14 which is provided with vertical end flanges 15 suitably secured to the opposite side walls of the casing 5. To this cross bar 14 is secured, as byybolts 16, an electric motor 18, the drive shaft 19 of which is concentric with the circular opening 12 and is arranged therein. A fan wheel, indicated generally at 20, is secured to the motor shaft 19. This fan wheel is shown as having a hub 21 fast to the motor shaft 1? and carrying a disk 22. To this disk are welded or otherwise suitably secured three fan blades 23 which are pitched to move the air from the inlet side of the casing to the outlet side thereof, this outlet'side being to the left as viewed in Fig. 2.

The large rectangular opening at each side of the fan casing 5 is closed by a foraminousgrid indicated generally at 25. Each grid consists of a relatively heavy marginal piece of wire 26 having its ends joined so as to be continuous and of a rectangular shape conforming to and fitting within the flanges 6 or S of the casing 5. The upper and lower stretches of this marginal wire rim 26 are connected by a'series of closely spaced vertical wires 28. The vertical sides of each rectangular marginal Wire rim 26 are connected by a central horizontal cross 'wire 29, a lower horizontal cross wire 30 and an upper horizontal cross wire 31, these cross wires preferably being secured to the vertical wires 28.

To removably secureeach grid 25 in the corresponding opening provided by the flange Ger 8, a pair of bracket plates 32 are provided within the bracket casing on each side of the partition 10. Each bracket plate has a base 33 welded to the bottom wall of the casing 10 and has a part extending angularly toward the bottom of the rectangular opening provided by the corresponding flange 6 or 8. Within this opening each flange has a reversely bent knuckle 34 which embraces and rotatably secures the lower horizontal run of the marginal wire rim 26 of the corresponding grid. It will therefore be seen that each grid can be swung downwardly, in the manner of the door, with the lower part of its marginal wire 26 acting as the pintle of a hinge, the knuckles of which are provided by the corresponding pair of'brackets 32.

To secure the grid in its operative position the opposite ends of the upper horizontal cross wire 31 are extended beyond the marginal wire rim 26 and are bent laterally upwardly and formed to provide a book 35 engagable in a small hole 36 provided in the corresponding rim 6 or 8. By moving each hook 35 laterally, it can be freed from the opening 36 so as to permit the corresponding grid 25 to be swung downwardly about the axes of the corresponding pair of brackets 32.

The fan as above described delivers a concentrated stream of air horizontally through the grid 25 contained within the opening provided by the flange 8 of the casing and it is the object of the present invention to spread this stream radially so as to dilfuse the same. To this end the present diliuser comprises an inner endless sheet metal ring 40 and an outer sheet metal ring 4-1, these being arranged in concentric relation to each other and with their upstream edges in the same plane and then downstream edges also in the same plane. Each of these rings is of forwardly enlarging form and of a curving rather than conical form in cross section. Thus, the upstream edge 42 of the inner ring 40 is of minimum diameter and the ring flares outwardly in curving cross section to a downstream edge of larger diameter 43. Similarly, as to the outer ring 41, its upstream edge 44 is of minimum diameter and the ring flares outwardly in curving cross section to a downstream edge of larger diameter 45.

At their top, bottom and sides, the two diifuser rings 40, 41 are connected by radial tie rods 46. Each tie rod 46 extends through an opening 48 in the inner ring 40 and has an enlarged head 49 hearing against the inner surface of this ring. The outer end of the tie rod extends through an opening 50 in the outer ring 41 and also through the base of a plastic gripper 51. The outer end of the tie rod also extends through a small Washer 52 and against the outer side of the gripper 51 and has its extremity peened over to provide a head 53.

These tie rods hold the two rings under slight radial stress, that is, they tend to expand the inner ring 40 and to contract the outer ring 41, and thereby serve to provide a non-rattling structure.

Each gripper 51 has an attaching portion 54 and an offset gripper portion 55, the offsetting of the gripper portion 55 from the base 54 providing a shoulder 56 which bears against the upstream edge 44 of the outer rim 41. The gripper portion 55 is bifurcated to provide two fingers 58 and a slot 59. The slot 59 is or" somewhat smaller size than the horizontal central Wire 29 or the vertical wires 28 of the grid so that when any of these Wires is forced into the slot 59, the wire will be securely gripped between the fingers 58. To this end each slot 59 is of somewhat keyhole form, slightly enlarging at its inner extremity.

In use, the diffuser structure as above described is placed against that grid 25 which encloses the discharge opening of the fan, namely, the opening provided by the flange 8. The upper and lower grippers 51 of the fan are arranged in line with the central vertical wire 28 of the grid and the horizontal grippers 51 are arranged in line with the hoizontal central wire 29 of the grid. Each gripper is then pressed rearwardly so that its fingers 58 embrace the corresponding wire 28 or 29 and so that this wire is caught in the inner enlarged extremity of the slot 59. Within this, the diffuser is securely attached to the grid 25 at the discharge side of the fan and in centered relation to the stream being discharged by the blades 23. The stream of air discharged by these blades encounter the two rings 40 and 41 of the diffuser and by reason of their enlarging form the stream is enlarged radially so as to diffuse the stream and avoid the discharge of a concentrated blast of air.

It will particularly be noted that by making the grippers 51 of plastic they are composed of relatively dead material which serves to dampen any tendency to produce noise by themselves and also to transmit vibration from the grid 25 to the diffuser rings. It will also be noted that these grippers 51 are mounted on the ends of the same tie rods 46 which secure the two rings 40, 41 together and that these grippers are held in operative position by the simple expedient of providing a shoulder 56 engaging the upstream edge 44 of the outer ring'41. It will also be seen that the tie rods 46 provide the sole connection between the rings 40 and 41 and operate, by slightly stressing these rings radially in opposition to each other to provide a strong and rigid and yet non-vibrating connection between these rings so that the diffuser as a whole is free from objectionable noise and vibration. It will also be seen that the diffuser has a pleasant and attractive appearance and can quickly and easily be applied to and removed from the fan.

We claim:

In combination with a household fan having a foraminous grid across its outlet, at ditfuser for enlarging radially the stream of air discharged from said fan, comprising a pair of diffusing rings consisting of an inner sheet metal diffusing ring having an upstream edge arranged adjacent said grid and flaring radially outwardly toward a larger downstream edge, and a concentric outer sheet metal diifusing ring having an upstream edge arranged adjacent said grid and flaring radially outwardly toward a larger downstream edge, a plurality of circumferentially spaced radially extending tie rods extending through said rings and each having a head on the inside of said inner ring and a head on the outside of said outer ring and holding said rings together under opposing radial stress whereby said tie rods are maintained under tension and said diffusing rings maintained under radial stress, and circumferentially spaced gripper means adjacent said outer ring for securing said rings and tie rods to said grid, each of said gripper means having penetrated by the outer end of a corresponding tie rod and including a shoulder engaging said upstream edge of said outer ring to prevent said gripper means from rotating about said tie rods.

References Cited in the file of this patent UNITED STATES PATENTS 701,228 Smith May 27, 1902 805,247 Thompson Nov. 21, 1905 1,192,857 Caldwell et a1 Aug. 1, 1916 2,199,525 Kurth May 7, 1940 2,307,586 Herbster Jan. 5, 1943 2,415,621 Arnhyn Feb. 11, 1947 2,571,726 Koch u Oct. 16, 1951 2,650,535 Hord Sept. 1, 1953 2,684,025 Kurth July 20, 1954 2,776,089 Burrowes et a1 Jan. 1, 1957 FOREIGN PATENTS 89,768 Sweden July 20, 1937 

